Lampreys are notorious for sucking blood, but they also produce antibody-like proteins with a taste for sugar that could help detect and deliver drugs to tumors. Dubbed lambodies, these proteins bind polysaccharides, or glycans, more tightly and specifically than most conventional antibodies, researchers have found (ACS Chem. Biol., DOI: 10.1021/cb300399s). The discovery provides a new source of reagents for detecting glycans linked to disease, such as those that decorate proteins and lipids made by tumor cells. To find lambodies that bind glycan biomarkers, Zeev Pancer of the University of Maryland’s Institute of Marine & Environmental Technology and colleagues screened a library of 100 million yeast clones that each expressed a different lambody on their surface. The researchers identified lambodies with affinities of up to 100 times that of conventional antibodies for glycans, including one linked to HIV and two found on most types of cancer cells. Pancer’s group aims to develop a lambody-based diagnostic biosensor to detect glycan biomarkers of cancer in patients’ blood, urine, or saliva.